B3764 Code: Meaning, Causes, and Symptoms | OBD2 Codes

B3764 – Auxiliary HVAC Door Actuator Range/Performance

 

B3764 Possible Symptoms

 

Engine Light ON (or Service Engine Soon Warning Light)

 

B3764 Possible Causes

 

Faulty Auxiliary Mode Actuator,Auxiliary Mode Actuator harness is open or shorted,Auxiliary Mode Actuator circuit poor electrical connection,Faulty Auxiliary Heating and Cooling Systems (HVAC) Control Module

 

B3764 Description

 

The Auxiliary Heating, Ventilation, and Air Conditioning (HVAC) Control Module controls the auxiliary HVAC door actuators to regulate the airflow through the auxiliary HVAC system. Each actuator consists of a stepper motor, a logic circuit, and a potentiometer. The potentiometer inside the door actuator allows the module to monitor the current position of the actuator drive shaft. The module supplies a 5-volt source voltage to the potentiometer on the 5-volt reference circuit. The module supplies ground to the potentiometer through the low reference circuit. The auxiliary HVAC control module monitors the voltage drop across the potentiometer on the door position signal circuit. When the actuator shaft rotates, the voltage on the door position signal circuit changes. The module converts the voltage value to a count value where 1 volt is approximately equal to 51 counts. The auxiliary HVAC control module calibrates the travel range of the auxiliary HVAC door actuators when it is initially powered by the battery positive voltage circuit. During calibration, the module commands the actuators in each direction until door travel is stopped. The module stores the minimum door positions and the maximum door positions of each actuator into memory. The total travel range is calculated by subtracting the minimum door position from the maximum door position. The door actuators can be calibrated again with a scan tool.